In a Long Term Evolution (LTE) system of the 3rd Generation Partnership Project (3GPP), for half-duplex FDD operations, during downlink-to-uplink switching, a terminal generates a guard period (GP), and in this guard period, the terminal does not receive data of a last part of a downlink subframe overlapping the guard period. However, neither a guard period nor a corresponding terminal behavior is defined for uplink-to-downlink switching.
To achieve low complexity or low costs of a half-duplex FDD terminal, when the half-duplex FDD terminal uses an oscillator to maintain a downlink receive frequency and an uplink transmit frequency, because an FDD system operates at different frequencies in the uplink and downlink, when the terminal switches from downlink to uplink, the oscillator needs to switch the frequency from a downlink frequency to an uplink frequency. When the terminal switches from uplink to downlink, the oscillator needs to switch the frequency from the uplink frequency to the downlink frequency.
However, when the oscillator switches a frequency channel number, an adjustment time is needed from a moment the oscillator performs the switching to a moment when the oscillator becomes stable, while the adjustment time leads to a change in a guard period for the uplink-to-downlink switching or downlink-to-uplink switching of the terminal, and if the guard period is not changed correspondingly, normal data transmission and receiving of the terminal are be affected. Therefore, new terminal behaviors need to be defined.